The present study was designed to determine the impact of secondary review of thyroid fine-needle aspiration (FNA) biopsy on surgical management. A retrospective review of patients referred to our institution with a thyroid FNA biopsy was conducted. Cytologic diagnoses from the report at our center and the referring institution were re-categorized by the Bethesda System for Reporting Thyroid Cytopathology. The rate of diagnostic disagreement was evaluated between Primary Diagnosis (PD) and Second Opinion Diagnosis (SOD), and the clinicopathologic correlations and the number of cases that prompted changes in treatment as a result of diagnostic disagreement were analyzed. 1499 patients meeting our study criteria were enrolled in this study. Diagnostic disagreement comprised 394 cases (26.3%). In the case of diagnostic disagreement, SOD was supported on clinicopathologic follow-up in 271 cases (68.8%), of which a change in management was made in 54 (13.7%) cases, and PD was supported in 93 (23.6%) cases, of which a change in management was made in 13 (3.3%) cases. By the second opinion, 65 (4.5%) patients received proper management, and 14 (1.0%) patients received superfluous management. Wide use of secondary cytopathologic review of thyroid FNA specimens from referring institutions was recommended.